Pharmacoeconomics of linezolid

Development and Validation of an LC-MS/MS Method for the Quantitative Determination of Contezolid in Human Plasma and Cerebrospinal Fluid

To develop and verify a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for determining contezolid in plasma and cerebrospinal fluid (CSF). Protein precipitation was performed on samples using linezolid as the internal standard. We used an Agilent EclipsePlus C18 column operating at 0.4 mL/min in conjunction with acetonitrile and water mobile phases for the LC-MS/MS analysis. Using the precursor-product ion pairs 409.15→269.14 (contezolid) and 338.14→195.1 (linezolid), multiple reaction monitoring was used to quantify the compounds. Plasma linearity range was 50.0 to 5000 ng/mL, and CSF was 20.0 to 1000 ng/mL (r² = 0.999). The inter-batch and intra-batch precisions were ≤2.57% and ≤5.79%, respectively. Plasma recovered 92.94%, and CSF recovered 97.83%. Plasma, CSF, hemolytic plasma, and hyperlipidemic plasma all showed a coefficient of variation ≤ 7.44%. The stability and dilution integrity of this method were also acceptable. The study also demonstrated that artificial CSF can be used as a matrix for the preparation of standard curve samples. A simple and accurate method was developed and validated for the determination of contezolid concentrations in human plasma and CSF, which may be useful for monitoring the therapeutic effect of central nervous system medications.

Economic evaluation among Chinese patients with nosocomial pneumonia caused by methicillin-resistant Staphylococcus aureus and treated with linezolid or vancomycin: a secondary, post-hoc analysis based on a Phase 4 clinical trial study

OBJECTIVE

To assess cost-effectiveness of linezolid vs vancomycin in treating nosocomial pneumonia caused by methicillin-resistant Staphylococcus aureus (MRSA-NP) in China and the impact of renal failure on healthcare resource utilization (HCRU) and costs.

METHODS

Cost-effectiveness analysis was conducted based on data from the ZEPHyR trial, with efficacy measured by treatment success and costs calculated from HCRU. Confidence intervals (CI) for cost, efficacy and incremental cost-effectiveness ratios (ICER) were calculated by non-parametric bootstrap. Chi-square test was used for renal failure rate and t-test for HCRU/cost comparisons. Impact of renal failure was assessed using regression model.

RESULTS

Data from 448 patients (1:1 linezolid:vancomycin) were analyzed. More patients treated with linezolid achieved success (55% [95% CI = 48-62%]) than with vancomycin (45% [38-52%]). Treatment cost were ¥79,551 (95% CI = ¥72,421-¥86,680) for linezolid vs ¥77,587 (¥70,656-¥84,519) for vancomycin in Beijing, ¥90,995 (¥82,598-¥99,393) vs ¥89,448 (¥81,295-¥97,601) in Guangzhou, ¥82,383 (¥74,956-¥89,810) vs ¥80,799 (¥73,545-¥88,054) in Nanjing and ¥59,413 (¥54,366-¥64,460) vs ¥57,804 (¥52,613-¥62,996) in Xi'an. Per successful treatment, the ICER of linezolid over vancomycin were ¥19,719 (-¥143,553 to ¥320,980) (Beijing), ¥15,532 (-¥185,411 to ¥349,693) (Guangzhou), ¥15,904 (-¥161,935 to ¥314,987) (Nanjing) and ¥16,145 (-¥100,738 to ¥234,412) (Xi'an). From simulations, the majority of linezolid cases had greater efficacy and higher costs and more than one third had greater efficacy and lower costs. More vancomycin patients developed renal failure (15% vs 4%, p < 0.001). Patients with renal failure had higher cost (Nanjng: ¥100,449 (SD = ¥65,080) vs ¥74,944 (SD = ¥49,632), p = 0.002).

CONCLUSION

Linezolid was more cost-effective than vancomycin in treating MRSA-NP from a Chinese payer's perspective, and associated with less renal failure, HCRU and cost.

Rising Methicillin-Resistant Staphylococcus aureus Infections in Ear, Nose, and Throat Diseases

The increasing incidence of methicillin-resistant Staphylococcus aureus infections (MRSA) in ENT diseases is becoming a big clinical concern. Here two patients are described who developed MRSA infections presented with unusual post-FESS epistaxis and postmastoidectomy perichondrial abscess and failed treatment with broad spectrum intravenous antibiotics. Following treatment with oral linezolid combined with local mupirocin dressing both patients fully recovered.

Cost comparison of linezolid versus vancomycin for treatment of complicated skin and skin-structure infection caused by methicillin-resistant Staphylococcus aureus in Quebec

BACKGROUND

In Canada, complicated skin and skin-structure infection (cSSSI) caused by methicillin-resistant Staphylococcus aureus (MRSA) is usually treated with antibiotics in hospital, with a follow-up course at home for stable patients. The cost implications of using intravenous and oral linezolid instead of intravenous vancomycin in Canadian clinical practice have not been examined.

OBJECTIVES

To evaluate the potential treatment cost impact for the Quebec health care system of linezolid versus vancomycin for MRSA-related cSSSI therapy, using a net impact analysis approach.

METHODS

Health care resource use associated with linezolid and vancomycin therapy was estimated for patients in Quebec, based on expert opinion. Costs were assigned to health care resources (antibiotics, medical supplies, laboratory testing and health care professional time) based on unit prices. The base-case analysis assumed 14 days of antibiotic treatment for both agents; five days in hospital followed by nine days at home. Therapy duration, length of inpatient treatment and discharge rates were varied in sensitivity analyses.

RESULTS

Antibiotic costs were higher for linezolid than for vancomycin, for both inpatient ($874 versus $144, respectively) and outpatient therapy ($1,356 versus $1,242, respectively). Compared with vancomycin, lower costs for antibiotic preparation, administration and monitoring of linezolid offset drug acquisition costs. Total treatment costs were $3,850 for linezolid versus $5,189 for vancomycin. Results were sensitive to the number of treatment days spent at home and the discharge rate.

CONCLUSION

Using linezolid instead of vancomycin to treat MRSA-related cSSSI, for hospital and home courses combined, may reduce health care resource utilization and costs in Quebec.

Multiresistant bacteria and current therapy - the economical side of the story

Severe infections with multiresistant bacteria (MRB) are a medical challenge and a financial burden for hospitals. The adequate antibiotic therapy is a key issue in multiresistant bacteria management. Several major cost drivers have been identified. Remarkably drug acquisition costs are not necessarily included. Most significant are the length of stay in hospital, the hours of mechanical ventilation and the time treated on an intensive care unit.

In a systematic review of the literature the following aspects were investigated:

- Do generic treatment strategies contribute in cost savings?

- Are there specific results for recent antibiotics?

Early adequate and effective antimicrobial treatment, switch from i.v. to oral therapy, adjusted duration of therapy and adherence to guidelines have been found to be successful strategies.

Looking at specific antibiotics, the best evidence for cost-effectiveness is found for Linezolid in treatment of cSSTI as well as in HAP. Daptomycin shows good economic results in bloodstream infections, so possibly being a cost-effective alternative to vancomycin. Looking at tigecycline the published data show neither higher costs nor savings compared to imipeneme. Doripenem as one of the newest therapy options has proven to be highly cost-saving in HAP when compared with imipenem. However, most analyses are based on pharmacoeconomic modelling rather than on directly analysing trial data or real life clinical populations.

A European survey of antibiotic management of methicillin-resistant Staphylococcus aureus infection: current clinical opinion and practice

Although the epidemiology of methicillin-resistant Staphylococcus aureus (MRSA) varies across Europe, healthcare-associated MRSA infections are common in many countries. Despite several national guidelines, the approach to treatment of MRSA infections varies across the continent, and there are multiple areas of management uncertainty for which there is little clinical evidence to guide practice. A faculty, convened to explore some of these areas, devised a survey that was used to compare the perspectives of infection specialists from across Europe on the management of MRSA infections with those of the faculty specialists. The survey instrument, a web-based questionnaire, was sent to 3840 registered delegates of the 19th European Congress of Clinical Microbiology and Infectious Diseases, held in April 2009. Of the 501 (13%) respondents to the survey, 84% were infection/microbiology specialists and 80% were from Europe. This article reports the survey results from European respondents, and shows a broad range of opinion and practice on a variety of issues pertaining to the management of minor and serious MRSA infections, such as pneumonia, bacteraemia, and skin and soft tissue infections. The issues include changing epidemiology, when and when not to treat, choice of treatment, and duration and route of treatment. The survey identified areas where practice can be improved and where further research is needed, and also identified areas of pan-European consensus of opinion that could be applied to European guidelines for the management of MRSA infection.

Newer developments in the treatment of Gram-positive infections

Gram-positive organisms are continually a major cause of infection. These organisms are ever-evolving and exhibit resistance to nearly all available agents. Historically, vancomycin was crowned the drug of choice for many of these organisms including methicillin-resistant Staphylococcus aureus, penicillin-resistant Streptococcus pneumoniae, and penicillin-resistant Enterococcus spp. Many of these organisms have exhibited reduced susceptibility or frank resistance to vancomycin which has resulted in treatment failure. For this reason, new strategies in treating Gram-positive infections are a hot topic. There are two general approaches to waging this war: i) development of new antimicrobial agents; and ii) reinvigorating old antibiotics that still retain appreciable activity against Gram-positives. We review both antibiotic groupings with a focus on S. aureus, S. pneumoniae and Enterococcus spp.

Health economic issues in the treatment of drug-resistant serious Gram-positive infections

Escalating health care costs have stimulated a paradigm change in the way health care is delivered, reimbursed, and evaluated. Reducing the length of hospital stay and controlling the cost of new technologies and therapies are major factors driving health care decisions. Economic evaluations have had variable success in the decision-making process, partly due to the overall quality, interpretation, and reporting of published analyses. Compared with other Gram-positive pathogens, the economic impact of methicillin-resistant Staphylococcus aureus (MRSA) infections remains the most studied. MRSA infections clearly represent a significant clinical and fiscal burden and future studies analyzing cost-effective strategies that encompass their prevention and optimal management would be beneficial. These studies would need to be carefully designed with clear objectives and explicit perspectives at the onset. Use of an appropriate reference group is key in the design process to measure the true impact of MRSA infections. Health-economic outcome data of the impact of linezolid compared with glycopeptides remain the most robust data available in this therapeutic area.

Linezolid for the treatment of drug-resistant infections

Multidrug-resistant pathogens have become increasingly common in contemporary healthcare. Specific to Gram-positive pathogens, methicillin-resistant Staphylococcus aureus (MRSA) is of particular concern, as it has been associated with increased hospital length of stay, higher healthcare expenditures and poorer outcomes. To date, linezolid is the first and only oxazolidinone approved by the US FDA for the treatment of infections caused by Gram-positive pathogens, including MRSA. This article will serve as a comprehensive review of linezolid, including an overview of the current market and its in vitro activity, with an in-depth review of its pharmacokinetic and pharmacodynamic profile. Emphasis will be placed on clinical data for the drug, both on- and off-label. The article will conclude with a brief overview of linezolid's pharmacoeconomic implications and safety profile, followed by a commentary and 5-year prospective analysis remarking on the future of the antimicrobial field as it relates to MRSA.